I am running into a strange problem when solving the 2D compressible Euler equations on a inclined wedge. To elaborate, my top boundary condition seems to emitting some type of instability. I have tried using Neumann BCs for the u,v velocities, but the issue still persists.
I am using a 2nd-order finite volume method on a curvilinear mesh (structured grid). My flux scheme is the Roe scheme with the Harten entropy fix. I have attached a movie that illustrates the problem.
I was curious if someone has any thoughts.